1. Field of the Invention
The present invention relates to a printing-plate mounting-position instruction system for instructing a user where to mount a plurality of printing plates in a rotary printing press that produces printed matter by the steps of, for example, superposing printed paper webs collected from a plurality of printing units; cutting the superposed, printed paper webs; and folding the resultant superposed, printed cut sheets.
2. Description of the Related Art
A rotary newspaper-printing press is one type of a rotary printing press that produces printed matter by the steps of, for example, superposing printed paper webs collected from a plurality of printing units; cutting the superposed, printed paper webs; and folding the resultant superposed, printed cut sheets.
One set of rotary newspaper-printing press includes 3 to 10 paper web supply units, at least the same number of printing units, and one folding unit. This rotary newspaper-printing press set produces copies of newspapers by the steps of, for example, printing each of paper webs supplied from the paper web supply units in a single color or a plurality of colors; superposing printed paper webs; cutting the superposed, printed paper webs; and folding the resultant superposed, printed cut sheets.
In large-scale newspaper printing facilities, a plurality of sets of newspaper-printing presses are concurrently operated to print newspapers. Up to 16 printing plates, each of which can print a broad-type page, can be mounted on one printing unit.
Accordingly, printing of newspaper involves usage of a large number of printing plates, which, needless to say, must be mounted at expected positions.
The total number of pages or the page(s) to be printed in a plurality of colors varies depending on the type of newspaper or the date of issue. Printing units to be used vary accordingly. As a result, the locations where printing plates are to be mounted in each printing unit are not fixed.
Further, in newspaper printing, news varies with time and the contents of pages depend on the region of distribution, and printing plates to be mounted vary accordingly.
Mounting of plating plates imposes a heavy burden on a worker. In some cases, a worker may mount a printing plate at a wrong position, resulting in a large amount of paper being wasted.
Various kinds of systems for preventing such a mistake in mounting printing plates are proposed in, for example, Japanese Utility Model Application Laid-Open (kokai) No. 62-121936 and Japanese Patent Application Laid-Open (kokai) Nos. 5-169638, 6-23970, 9-300594, 10-52906, 10-128955, and 10-202840.
According to Japanese Utility Model Application Laid-Open No. 62-121936, a printing system includes a plurality of printing units and one folding unit. Each of the printing units include a plate cylinder on which a plurality of printing plates is mounted in a predetermined order. The folding unit is adapted to cut printed paper webs collected from the printing units and to fold the resultant printed cut sheets. The location where a printing plate is to be mounted on a plate cylinder of a printing unit selected for a certain printing job is determined on the basis of printing-unit selection information. The determined printing-plate mounting position is displayed in a digital form.
According to Japanese Patent Application Laid-Open (kokai) No. 5-169638, a printing plate bears a printing-plate identification mark containing printing-plate position information at an end edge portion, which is not involved in printing. The printing plate is mounted on a plate cylinder such that the printing-plate identification mark is visible from the outside. The mounted printing plate is irradiated with a light beam that contains cylinder position information regarding the plate-cylinder position, in order to read the printing-plate identification mark. The printing-plate position information is obtained from the printing-plate identification mark, while the cylinder position information is obtained from the light beam. Subsequently, the printing-plate position information is collated with the cylinder position information, thereby enabling automatic judgment of whether the printing plate is mounted at an expected position on the plate cylinder.
According to Japanese Patent Application Laid-Open (kokai) No. 6-23970, in a rotary newspaper-printing press, characters, marks, or figures are sensed from a traveling printed paper web, and the sensed characters, marks, or figures are processed for identification of printing information. The identified printing information is compared with that received from a higher-order controller. The result is displayed along with a warning if needed.
According to Japanese Patent Application Laid-Open (kokai) No. 9-300594, printing-plate mounting regions on a plate cylinder each bear a cylinder position identification mark containing cylinder position information, or a printing-plate identification mark containing printing-plate position information. Printing plates mounted in the respective printing-plate mounting regions each bear the printing-plate identification mark containing printing-plate position information, or the cylinder position identification mark containing cylinder position information. The cylinder position identification mark and the printing-plate identification mark are read so as to obtain the cylinder position information and the printing-plate position information, respectively. The read cylinder position information and printing-plate position information are input to a judging device, in which the cylinder position information and the printing-plate position information are collated with preset cylinder position information and preset printing-plate position information which are previously fetched in the judging device, thereby enabling automatic judgment of whether the printing plates are mounted at expected positions.
Japanese Patent Application Laid-Open (Kokai) No. 10-52906 discloses a printing-plate mounting-position marking printer and a method for mounting a printing plate onto a plate cylinder on the basis of marking printed by the printer. Specifically, a printing plate is marked with a cylinder position identification mark that contains mounting-cylinder position information. The cylinder position identification mark is read so as to obtain the mounting-cylinder position information. The printing-plate mounting-position marking printer prints the read mounting-cylinder position information in a printing area on the printing plate in a hydrophilic ink, so that the printed information becomes visible to a worker.
Japanese Patent Application Laid-Open (kokai) No. 10-128955 discloses a printing-plate mounting-position marking printer and a method for mounting a printing plate, which printer and method are substantially identical with those disclosed in Japanese Patent Application Laid-Open (kokai) No. 10-52906, except that the mounting-cylinder position information is printed on the back side of a printing plate and that ink is not particularly limited to a hydrophilic ink.
Japanese Patent Application Laid-Open (kokai) No. 10-202840 discloses a printing-plate mounting-position checking apparatus. The apparatus has a function of visibly printing mounting-cylinder position information on a printing plate in such an ink that does not affect printing, on the basis of a cylinder position identification mark which contains mounting-cylinder position information and which is stored in a cylinder position identification mark memory. The apparatus further provide a collation function for the printing plate that is attached to the plate cylinder after visual confirmation of the mounting-cylinder position information printed on the printing plate. That is, the apparatus reads the mounting-cylinder position information marked on the printing plate which a worker has mounted onto the plate cylinder, through identification by the marked information, and collates the read mounting-cylinder position information with that of the cylinder position identification mark stored in the memory.
Japanese Patent Application Laid-Open (kokai) No. 10-202840 further discloses a printing-plate mounting-position checking apparatus and a method for mounting a printing plate onto a plate cylinder according to mounting-cylinder position information marked on the printing plate. The apparatus has a function of reading a cylinder position identification mark provided on a printing plate for mounting-cylinder position information and visibly printing the read mounting-cylinder position information on the printing plate in such an ink that does not affect printing. The apparatus further provide a collation function for the printing plate that is attached to the plate cylinder after visual confirmation of the mounting-cylinder position information printed on the printing plate. That is, the apparatus reads the mounting-cylinder position information marked on the printing plate which a worker has mounted onto the plate cylinder, through identification by the marked information, and collates the read mounting-cylinder position information with that contained in the previously read cylinder position identification mark.
The above-described techniques involve the following problems.
According to Japanese Utility Model Application Laid-Open No. 62-121936, printing plates are theoretically assigned to mounting positions on a plate cylinder of each of printing units selected for a certain printing job, and the assignment is displayed in digital form. However, individual printing plates are not marked with information regarding locations where they are to be mounted, or the locations where individual printing plates are to be mounted are not instructed.
In the end, a worker must check the contents of a printing plate in order to determine where the printing plate is to be mounted; specifically, a mounting position on a specific plate cylinder of a specific printing unit.
Thus, a mental burden imposed on a worker during mounting of printing plates cannot be lessened. Further, it becomes impossible to reliably prevent an incident in which the worker mistakenly mounts a printing plate at a wrong position.
According to Japanese Patent Application Laid-Open (kokai) No. 5-169638, printing-plate position information is read from a printing-plate identification mark provided at a non-printing portion of a printing plate mounted on a plate cylinder. The read printing-plate position information is collated with cylinder position information obtained from a beam which is radiated onto each of printing-plate mounting positions, thereby enabling judgment of whether the printing plate is mounted properly. Thus, when a printing plate is to be mounted, a worker must check the contents of the printing plate in order to determine where the printing plate is to be mounted; specifically, a mounting position on a specific plate cylinder of a specific printing unit.
Thus, a mental burden imposed on a worker during mounting of printing plates cannot be lessened. Further, it becomes impossible to reliably prevent an incident in which the worker mistakenly mounts a printing plate at a wrong position.
Whether a printing plate is mounted at an expected position is checked as described above. However, when, due to a certain reason or accident, a printing unit to be used is changed to any other printing unit after a printing-plate identification mark is marked on a printing plate with a resultant change in the order of superposing printed paper webs collected from printing units, the printing-plate position information read from the printing-plate identification mark on the printing plate becomes inconsistent with the change of printing units. As a result, it becomes impossible to judge whether the printing plate is mounted at an expected position.
According to Japanese Patent Application Laid-Open (kokai) No. 6-23970, a predetermined printed image read from a traveling printed paper web is compared with printing information contained in a higher-order controller, thereby enabling judgment of whether printing is performed at a predetermined position. However, when a printing plate is to be mounted, a worker must check the contents of the printing plate in order to determine where the printing plate is to be mounted; specifically, a mounting position on a specific plate cylinder of a specific printing unit.
Thus, a mental burden imposed on a worker during mounting of printing plates cannot be lessened. Further, it becomes impossible to reliably prevent an incident in which the worker mistakenly mounts a printing plate at a wrong position.
Further, since whether a printed image is located at an expected position is checked after the start of printing, mounting of a printing plate at a wrong position results in a large amount of paper being wasted.
According to Japanese Patent Application Laid-Open (kokai) No. 9-300594, printing-plate mounting regions on a plate cylinder each bear an identification mark, and printing plates mounted in the respective printing-plate mounting regions each bear an identification mark. The identification marks are read so as to obtain cylinder position information or printing-plate position information. Based on the read information, judgment is made as to whether each of the printing plates is mounted at an expected position.
Thus, a mental burden imposed on a worker during mounting of printing plates cannot be lessened. Further, it becomes impossible to reliably prevent an incident in which the worker mistakenly mounts a printing plate at a wrong position.
Whether a printing plate is mounted at an expected position is checked as described above. However, when, due to a certain reason or accident, a printing unit to be used is changed to any other printing unit after a printing-plate identification mark is marked on a printing plate with a resultant change in the order of superposing printed paper webs collected from printing units, the cylinder position information or printing-plate position information contained in the identification mark marked on a printing plate becomes inconsistent with that contained in an identification mark associated with the printing unit where the printing plate is actually mounted. As a result, it becomes impossible to judge whether the printing plate is mounted at an expected position.
According to Japanese Patent Application Laid-Open (kokai) Nos. 10-52906 and 10-128955, a cylinder position identification mark marked on a printing plate is read. Subsequently, based on the mounting-cylinder position information contained in the read cylinder position identification mark, information representing the mounting position of the printing plate is printed on the printing plate so as to be visible to a worker. Referring to the printed information, the worker mounts the printing plate onto the relevant plate cylinder. Thus, a mental burden that would otherwise be imposed on the worker during mounting of printing plates can be lessened.
However, a printing mechanism, such as an ink-jet printing mechanism, for reading out an identification mark of a printing plate and for printing information regarding the mounting position of the printing plate is required, causing an increase in equipment cost, operating cost, and labor, such as maintenance of the printing mechanism.
Also, when, due to a certain reason or accident, a printing unit to be used is changed to any other printing unit after a cylinder position identification mark is marked on a printing plate with a resultant change in the order of superposing printed paper webs collected from printing units, the mounting-cylinder position information printed on the printing plate becomes inconsistent with the newly expected mounting position, potentially causing a worker to mount the printing plate at a wrong position.
As in the case of Japanese Patent Application Laid-Open (kokai) Nos. 10-52906 and 10-128955, according to Japanese Patent Application Laid-Open (kokai) No. 10-202840, information regarding where to mount a printing plate is printed on the printing plate so as to be visible to a worker. After the printing plate is mounted onto a plate cylinder according to the printed information, the printed information is read from the mounted printing plate and is collated with reference information for checking whether the mounted printing plate is an expected one.
Thus, a mental burden that would otherwise be imposed on the worker during mounting of printing plates can be lessened.
However, a printing mechanism, such as an ink-jet printing mechanism, for reading out an identification mark of a printing plate and for printing information regarding the mounting position of the printing plate is required, causing an increase in equipment cost, operating cost, and labor, such as maintenance of the printing mechanism.
Also, when, due to a certain reason or accident, a printing unit to be used is changed to any other printing unit after a cylinder position identification mark is marked on a printing plate, with a resultant change in the order of superposing printed paper webs collected from printing units, the mounting-cylinder position information printed on the printing plate becomes inconsistent with the newly expected mounting position, potentially causing the worker to mount the printing plate at a wrong position.
According to claim 1 of Japanese Patent Application Laid-Open (kokai) No. 10-202840, a printing plate is not marked with an identification mark, but is printed with information regarding the position where the printing plate is to be mounted. The publication does not definitely describe how the contents of a printing plate are recognized and associated with the information regarding the position where the printing plate is to be mounted. In any case, when a printing unit to be used is changed to any other printing unit after the printing plate is printed with the information regarding the position where the printing plate is to be mounted, the printed information becomes inconsistent with the newly expected mounting position, potentially causing a worker to mount the printing plate at a wrong position.
Further, even when a plate cylinder to which a printing plate has been mounted is checked as to whether the mounted printing plate is valid, on the basis of the mounting-position information printed on the printing plate, this check becomes invalid when the printing units are changed as mentioned above. This is because the printed information becomes inconsistent with the newly expected mounting position of the printing plate.